Immersion Lithography Fluids

ABSTRACT

Suitable additives that may be added into immersion fluids, immersion fluids comprising at least one carrier medium selected from an aqueous fluid, a non-aqueous fluid, and mixtures thereof, and immersions fluids comprising at least one carrier medium and at least one additive useful for performing immersion lithography at an operating wavelength ranging from 140 nm to 365 nm are disclosed herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/030,132, filed 07 Jan. 2005, which is a continuation-in-part of U.S.patent application Ser. No. 10/764,227, filed 23 Jan. 2004, thedisclosures of which are incorporated herein by reference in theirentirety.

BACKGROUND

Immersion lithography may offer better resolution enhancement and highernumerical apertures at a given exposure wavelength over conventionalprojection lithography. For example, immersion lithography could extendlithography at the 193 nm wavelength down to the 45 nm node and belowthereby providing an alternative to 157 nm exposure wavelengths, extremeultraviolet (EUV), and other potential technologies.

The minimum feature width (W) that may be printed with an opticallithography system is determined by the Rayleigh equation: W=(k₁λ)/(NA)where k₁ is the resolution factor, λ is the wavelength of the exposingradiation and NA is the numerical aperture. Numerical aperture (NA) isdetermined using the equation: NA=n sin α where n is the index ofrefraction of the medium surrounding the lens and α is the acceptanceangle of the lens. The physical limit to NA for exposure systems usingair as a medium between the lens and the wafer is 1. Air is the worstmedium because its index of refraction may cause a relatively highamount of bending when light leaves the glass. Since the index ofrefraction for water and glass is approximately 1.44 and 1.52respectively, far less bending occurs thereby providing a sharper anddeeper focus.

In immersion lithography, the space between the lens and the substrateis filled with a liquid, referred to herein as an immersion fluid, thathas a refractive index greater than 1. The immersion fluid shouldpreferably exhibit a low optical absorption at the operating wavelengthsuch as, for example 193 nm and 157 nm, be compatible with thephotoresist and the lens material, be uniform and be non-contaminating.A preferred immersion fluid for 193 nm immersion lithography is ultrapure water. Ultra pure water has an index of refraction of approximately1.44, exhibits absorption of less than 5% at working distances of up to6 mm, is compatible with photoresist and lens, and is non-contaminatingin its ultra pure form. Applying the Rayleigh equation using n=1.44 andassuming sin α can reach 0.93, the feature width for 193 nm could reacha theoretical minimum resolution of 36 nm. Still other immersion fluidsthat have been considered for 15 nm immersion lithography are KRYTOX™and perfluoropolyether (PFPE).

To date, immersion lithography has not been widely implemented incommercial semiconductor processing partly because improvements inresolution by conventional methods have been possible, but also partlybecause of practical limitations in implementing immersion lithography.The wafer stage of a typical 193 nm exposure tool steps from location tolocation across the wafer scanning the reticle image for each field. Inorder to achieve high throughput, the stage should accelerate rapidly,move accurately to the next field location, settle, scan the image, andthen step to the next location within a short time interval. Theimmersion fluid is typically introduced between the lens and the resistsurface of the substrate using a jet stream of the immersion fluid. Thespace between the lens and the resist surface, referred to herein as theworking distance, is less than 6 mm or typically 1 mm. Due to a varietyof factors such as short process cycle time, minimal working distance,and dynamics of the immersion stream, maintaining a consistent bubblefree liquid between the lens and the resist-coated wafer is verydifficult. Further, there is a lack of immersion fluids that haveappropriate optical transmission characteristics and chemicalcompatibility with lithographic systems.

The desire to develop immersion systems is growing more acute becausethe ability to achieve resolution improvements via conventional means,such as wavelength reduction, appears to be increasingly difficult,particularly at wavelengths below 365 nm. In addition, with numericalapertures or NAs produced by lithographic methods using air as theimmersion medium approaching the theoretical limit, progress usingconventional methods is bounded. Accordingly, there is a need for animmersion fluid that is compatible with immersion lithographic systems,particularly those systems having an operative wavelength below 365 nm.

BRIEF SUMMARY

Immersion fluids comprising at least one carrier medium, immersionfluids comprising at least one carrier medium and at least one additivetherein are disclosed herein. In one aspect of the present invention,there is provided an immersion fluid comprising: about 1 ppm to amaximum solubility limit of at least one additive selected from an alkylalcohol; an alkyl ethoxylate, an alkyl propoxylate, and derivativethereofs; an alkyl acid ester; an alkyl amine comprising an amine group;an alkyl amine ethoxylate; an acetylenic alcohol, an acetylenic diol,and ethylene oxide/propylene oxide derivatives thereof; an alkylpolyglycoside; a block oligomer; a polymer of ethylene and propyleneoxide; a glycidyl ether; a glucamine derivative of a glycidyl ether; anurea; a siloxane-containing compound; a fluorinated or partiallyfluorinated acetylenic alcohol, diol and derivatives thereof; afluorosurfactant; an ionic liquid; a salt; and an electrolyte, providedthat if the at least one additive is a fluorosurfactant then theimmersion fluid comprises about 1% by weight or greater of an aqueousfluid.

In another aspect of the invention, there is provided immersion fluidhaving a transmission of 50% or greater at an operating wavelengthranging from 140 nm to 365 nm comprising: at least one carrier mediumselected from the group consisting of an aqueous fluid, a non-aqueousfluid, and mixtures thereof wherein the at least one carrier medium hasa refractive index greater than or equal to water at the operatingwavelength; and from about 1 ppm to the maximum solubility limit of atleast one additive selected from an alkyl alcohol; an alkyl ethoxylate,an alkyl propoxylate, and derivative thereofs; an alkyl acid ester; analkyl amine comprising an amine group; an alkyl amine ethoxylate; anacetylenic alcohol, an acetylenic diol, and ethylene oxide/propyleneoxide derivatives thereof; an alkyl polyglycoside; a block oligomer; apolymer of ethylene and propylene oxide; a glycidyl ether; a glucaminederivative of a glycidyl ether; an urea; a siloxane-containing compound;a fluorinated or partially fluorinated acetylenic alcohol, diol andderivatives thereof; a fluorosurfactant; an ionic liquid; a salt; and anelectrolyte, provided that if the at least one additive is afluorosurfactant then the immersion fluid comprises about 1% by weightor greater of an aqueous fluid.

In a further aspect of the present invention, there is provided animmersion fluid having a transmission of 50% or greater at an operatingwavelength ranging from 140 nm to 365 nm comprising: at least onecarrier medium selected from an aqueous fluid, a non-aqueous fluid, anda mixture of the non-aqueous fluid and the aqueous fluid wherein the atleast one carrier medium has a refractive index greater than or equal towater at the operating wavelength and wherein if the at least onecarrier medium is the mixture then the non-aqueous fluid is watermiscible.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 provides the dynamic contact angle measurements for variousembodiments of the immersion fluid of the present invention on unexposed193 nm photoresists.

FIG. 2 provides the absorbance spectra of ultra pure water and anembodiment of the immersion fluid of the present invention that wasmeasured using a UV spectrometer.

FIG. 3 provides comparison of the change in film thickness (nm) forvarious embodiments of the immersion fluid of the present inventioncompared to ultra pure water.

FIG. 4 compares the absolute refractive index of various immersionfluids disclosed herein measured at a wavelength of 193 nm.

FIG. 5 provides the dynamic contact angle measurements for variousembodiments of the immersion fluid of the present invention on unexposed193 nm photoresists.

DETAILED DESCRIPTION

Immersion fluids, comprising at least one carrier medium or comprisingat least one carrier medium and at least one additive, useful forperforming immersion lithography at operating wavelengths ranging from140 to 365 nm, particularly 157 nm and/or 193 nm wavelengths aredisclosed herein. The term “carrier medium” as used herein relates to anaqueous fluid, a non-aqueous fluid, or a mixture thereof that may beused by itself or have at least one additive added thereto to provide animmersion fluid. The term “fluid” as used herein describes a gas,liquid, a nanoparticle suspension, a supersaturated liquid, vapors, andcombinations thereof. In embodiments wherein the aqueous fluid,non-aqueous fluid, and/or immersion fluid comprises a nanoparticlesuspension, the average particle size of the nanoparticles containedtherein is about 20% or less of the operating wavelength.

It is believed that the presence of the at least one additive within theat least one carrier medium such as, for example, a salt, a surfactant,an electrolyte or mixtures thereof within an immersion fluid, or theimmersion fluid comprising at least one carrier medium without theaddition of at least one additive, may provide at least one of thefollowing benefits: improve the wetting of the immersion fluid onto theresist-coated substrate; reduce defect formation by substantiallyminimizing the formation of micro-bubbles and nano-bubbles; protect theresist surface by forming aggregations of one or more monolayers at theresist-immersion fluid interface or resist-protective-layer andimmersion fluid interface thereby preventing leaching of any chemicalsfrom the resist; minimize the feature size and maximize the resolutionwhen added into an immersion fluid with a refractive index equal to orgreater than water at the operating wavelength, such as for example arefractive index equal to or greater than 1.44 at an operatingwavelength of 193 nm, thereby allowing smaller feature sizes to beachieved; increase the refractive index of the immersion fluid if thecarrier medium such as water has a low absorbance at wavelengths rangingfrom 140 to 365 nm provided that there is no interaction between thephotoresist and the optics; and minimize the change in feature size uponexposure to light or heat by adding at least one additive to the carriermedium having the opposite refractive index/temperature characteristics(dn/dT) that may minimize or eliminate the change in refractive indexupon exposure to laser light or heat. Further, the addition of at leastone additive to a carrier medium, or the carrier medium itself, mayprovide an immersion fluid that does not significantly increase theabsorbance of the immersion fluid at one or more operating wavelengthsor maintains the absorbance below 5%, or below 1%, or below 0.5%. Theimmersion fluid containing at least one carrier medium and at least oneadditive, or the immersion fluid containing at least one carrier medium,may exhibit 50% or greater, 80% or greater, or 90% or greater totaltransmission.

As mentioned previously, the immersion fluid may comprise at least onecarrier medium that is an aqueous fluid, a non-aqueous fluid, or amixture thereof that may have at least one additive added thereto, oralternatively, the immersion fluid may be the carrier medium itself.

In certain embodiments, the carrier medium may comprise an aqueousfluid. In these embodiments, the refractive index may be equal to orgreater than the refractive index of water at the operating wavelengthsuch as, for example, a refractive index of 1.44 at an operatingwavelength of 193 nm. Further, the aqueous fluid transmits light at theoperating wavelengths of the lithography system such as a wavelengthranging from 140 to 365 nm. The term “aqueous” as used herein, describesa fluid dispersing medium, which comprises at least 80 weight percent,preferably 90 weight percent, and more preferably at least 95 weightpercent water. Examples of suitable aqueous fluids include deionizedwater, ultra pure water, distilled water, doubly distilled water, andhigh performance liquid chemical (HPLC) grade water or deionized waterhaving a low metal content.

In certain embodiments, the carrier medium may comprise a non-aqueousfluid. In these embodiments, the non-aqueous fluid is used in additionto, or in place of, an aqueous fluid. In these embodiments, thenon-aqueous fluid selected preferably does not react with othercomponents in the immersion fluid, the photoresist coating on thesubstrate, the system optics, or the substrate itself. In embodimentswherein the immersion fluid has at least one additive contained therein,the non-aqueous fluid preferably does not react with the at least oneadditive contained therein. Suitable fluids include, but are not limitedto, hydrocarbons and derivatives thereof, including but not limited to,cyclic alkanes and acyclic alkanes (e.g. dodecane, hexane, pentane,hexadecane, cyclohexane, bicyclohexyl, tricyclohexane,decahydronapthalene, and cyclopentane; fluorinated (partially or fully)hydrocarbons and derivatives thereof (e.g., perfluorocyclohexane andperfluorodecalin); SF₅-functionalized hydrocarbons; halocarbons (e.g.Freon 113); ethers (e.g. ethylether (Et₂O), tetrahydrofuran (“THF”),ethylene glycol and derivatives thereof, monomethyl ether, or2-methoxyethyl ether (diglyme)), and esters and derivatives thereof(e.g. sodium octanoate and sodium perfluorooctanoate). Still furtherexemplary fluids include lactates, pyruvates, and diols. These fluidsinclude ketones such as, but are not limited to, acetone, ethyl acetate,cyclohexanone, acetone, N-methyl pyrrolidone (NMP), and methyl ethylketone. Other exemplary non-aqueous fluids include amides such as, butnot limited to, dimethylformamide, dimethylacetamide, acetic acidanyhydride, propionic acid anhydride, and the like. Exemplarynon-aqueous fluids can include, but are not limited to,sulfur-containing compounds such as mercaptans (e.g., lauryl mercaptan),sulfones (e.g., dimethyl sulfone, diphenyl sulfone, sulfoxides (e.g.,dimethyl sulfoxide). Still further non-aqueous fluids include alcoholssuch as, for example, propylene glycol propyl ether (PGPE), methanol,tetrahydrofurfuryl alcohol, 1-methylcyclohexanol, cyclohexanol,2-methylcyclohexanol, adamantemethanol, cyclopentanol,dimethyl-3-heptanol, dimethyl-4-heptanol, dodecanol, oleyl alcohol,pentanol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butanediol, 1,2-propyleneglycol, 1,3-propylene glycol, 1-dodecanol, cyclooctane, ethanol,3-heptanol, 2-methyl-1-pentanol, 5-methyl-2-hexanol,cis-2-methylcyclohexanol, 3-hexanol, 2-heptanol, 2-hexanol,2,3-dimethyl-3-pentanol, propylene glycol methyl ether acetate (PGMEA),ethylene glycol and derivatives thereof, polyethylene glycol andderivatives thereof, isopropyl alcohol (IPA), n-butyl ether, propyleneglycol n-butyl ether (PGBE), 1-butoxy-2-propanol, 2-methyl-3-pentanol,2-methoxyethyl acetate, 2-butoxyethanol, 2-ethoxyethyl acetoacetate,1-pentanol, propylene glycol methyl ether, 3,6-dimethyl-3,6-octanol,maltose, sorbitol, mannitol, super, fully, and partially hydrolyzedpoly(vinyl)alcohol, 1,3-butanediol, glycerol and derivatives thereofsuch as thioglycerol. Further non-aqueous fluids may comprise an acidsuch as, for example, sulfuric acid, lactic acid, octanoate acid,polyphosphoric acid, phosphoric acid, hexafluorophosphoric acid,tartaric acid, methane sulfonic acid, trifluoromethane sulfonic acid,dichloroacetic acid, propionic acid, and citric acid. Yet anothernon-aqueous fluid can be a silicone such as silicone oil. Still furthernon-aqueous fluids include 1,4-dioxane, 1,3-dioxolane, ethylenecarbonate, propylene carbonate, ethylene carbonate, propylene carbonate,and m-cresol. The non-aqueous fluids enumerated above may be used alone,in combination with one or more other non-aqueous fluids, or incombination with an aqueous fluid.

In certain embodiments, the carrier medium may comprise a mixture of atleast one aqueous fluid and at least one non-aqueous fluid. In theseembodiments, the immersion fluid may contain at least one non-aqueousfluid that is miscible in the aqueous fluid or is water-miscible. Theamount of non-aqueous fluid within the immersion fluid may range fromabout 1 to about 99%, or from about 1 to about 50% by weight with thebalance of the carrier medium within the immersion fluid comprising anaqueous fluid. Examples of water-miscible non-aqueous fluids include,but are not limited to, methanol, ethanol, isopropyl alcohol, glycerol,ethylene glycol and derivatives thereof, polyethylene glycol andderivatives thereof and THF.

In certain embodiments, certain non-aqueous fluids, having a refractiveindex greater than or equal to that of water and a specific absorbanceof less than 1 cm⁻¹ or less than 0.5 cm⁻¹ at one or more operatingwavelengths ranging from 140 to 365 nm may be added to the immersionfluid in the amount ranging from 0.1 to 100%, or from 1 to 50% toincrease the refractive index of the immersion fluid. At an operatingwavelength of 193 nm, the non-aqueous fluid may have a refractive indexequal to or greater than that of water or greater than 1.44. Exemplarynon-aqueous fluids that may be used at this operating wavelengthinclude, but are not limited to, citric acid (n=1.496), bicyclohexyl(n=1.477), glycerol (n=1.4730), or cis-2-methylcyclohexanol (n=1.4633).

In certain embodiments, the immersion fluid comprises from 10 parts permillion (ppm) to the maximum solubility limit, or from 1 ppm to 50% byweight, or from 10 ppm to 10,000 ppm of at least one additive. The term“maximum solubility limit” as used herein relates to the maximum amountof the at least one additive that can be added to the carrier medium toprovide a homogenous solution without phase separation and/orprecipitation of the at least one additive. Examples of at least oneadditive that may be used alone, or in combination with one or moreother at least one additives, within an immersion fluid include: analkyl alcohol such as, for example, a polymeric alcohol having one ormore hydroxyl groups; an alkyl ethoxylate, an alkyl propoxylate, and(PO) derivatives thereof which may further include mono- and multi-hydrophilic units (such as diols); an alkyl acid ester such as, forexample, an alkyl carboxylate or an alkyl acid ester with mono- andmulti-carboxyl units; an alkyl amine such as one having one or moreamine groups including primary, secondary and tertiary amines; an alkylamine ethoxylate; an acetylenic alcohol, an acetylenic diol, andethylene oxide/propylene oxide derivatives thereof; an alkylpolyglycoside; a block oligomer; a polymer of ethylene and propyleneoxide; a glycidyl ether or a glucamine derivative of the glycidyl etherwith an at least one selected from an alkyl amine, an alkyl diamine, analkyl alcohol, an acetylenic alcohol, and combinations thereof; a ureasuch as an alkyl urea or a dialkyl urea; a siloxane-containing compoundsuch as, for example, a polysiloxane, a poly(dimethyl)siloxane, apolysiloxane polyester copolymer, or derivatives thereof; a fluorinatedor partially fluorinated acetylenic alcohol, diol or derivativesthereof; a fluorosurfactant; a salt; and an electrolyte. The additivesenumerated above may be used alone or in combination with one or moreother additives.

In certain embodiments, at least one additive is a surfactant. Typicalsurfactants exhibit an amphiphilic nature, meaning that they can be bothhydrophilic and hydrophobic at the same time. Amphiphilic surfactantspossess a hydrophilic head group or groups, which have a strong affinityfor water and a long hydrophobic tail, which is organophilic and repelswater. In embodiments wherein the at least one additive is a surfactant,the surfactant may be ionic (i.e., anionic, cationic, amphoteric) ornonionic.

In certain embodiments of the present invention, the immersion fluid maycontain at least one additive that is an acetylenic alcohol, anacetylenic diol, or an ethylene oxide/propylene oxide derivativethereof. Exemplary acetylenic alcohol, acetylenic diol or ethyleneoxide/propylene oxide derivatives that can be used as the at least oneadditive within an immersion fluid may be represented by the followingformulas I through III:

wherein R₁ and R₄ are each independently a straight or a branched alkylchain having from 3 to 10 carbon atoms; R₂ and R₃ are each independentlya hydrogen atom or an alkyl chain having from 1 to 5 carbon atoms; andm, n, p, and q are each independently a number that ranges from 0 to 20.The at least one additive having the formula I, II or III arecommercially available from Air Products and Chemicals, Inc. ofAllentown, Pa., the assignee of the present invention, under the tradenames SURFYNOL® and DYNOL®. In certain embodiments, the acetylenic diolportion of the molecule of formulas I or II is2,4,5,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol. The at least one additives having theformulas I through III may be prepared in a number of ways including themethods described, for example, in U.S. Pat. No. 6,313,182 and EP1115035A1, which are assigned to the assignee of the present inventionand incorporated herein by reference in their entirety.

In formulas I and II, the alkylene oxide moieties represented by (OC₂H₄)are the (n+m) polymerized ethylene oxide (EO) molar units and themoieties represented by (OC₃H₆) are the (p+q) polymerized propyleneoxide (PO) molar units. The value of (n+m) may range from 0 to 30,preferably from 1.3 to 15, and more preferably from 1.3 to 10. The valueof (p+q) may range from 0 to 30, preferably from 1 to 10, and morepreferably from 1 to 2.

In other embodiments, the immersion fluid may contain from 1 ppm to themaximum solubility limit or from 1 ppm to 50% by weight or from 10 ppmto 10,000 ppm of at least one additive that is represented by thefollowing formulas (IV) through (XI):

In each of the above formulas, R, R₁ and R₄ are each independently astraight, branched, or cyclic alkyl, fluoroalkyl, or perfluoroalkylgroup having from 2 to 25, or from 3 to 10 carbon atoms; R₂ and R₃ areeach independently a hydrogen atom, a straight, a branched or a cyclicalkyl group, fluoroalkyl group, or perfluoroalkyl group having from 1 to10 or from 1 to 5 carbon atoms; R₅ is a straight, a branched, or acyclic alkyl, fluoroalkyl, or perfluoroalkyl group having from 1 to 10carbon atoms; R₆ is a straight, a branched, or a cyclic alkyl,fluoroalkyl, or perfluoroalkyl group having from 4 to 16 carbon atoms;R₇, R₈ and R₉ are each independently a straight, a branched, or a cyclicalkyl, fluoroalkyl or perfluoroalkyl group having from 1 to 6 carbonatoms; R₁₀ is independently H or a group represented by the formula

R₁₁ is a straight, a branched, or a cyclic alkyl group having from 4 to22 carbon atoms; W is a hydrogen atom or an alkynyl group; X and Y areeither a hydrogen atom or a hydroxyl group; Z⁻ is either a halide atom,a hydroxyl group, an acetate group, or a carboxylate group; m, n, p, qare each independently a number ranging from 0 to 20; r and s are eachindependently 2 or 3; t is a number ranging from 0 to 2; i is a numberranging from 0 to 20; x is a number ranging from 1 to 6, and M is amonovalent metal ion or an ammonium ion.

The at least one additive may be an alkyl alcohol such as, for example,a polymeric alcohol having one or more hydroxyl groups. Exemplary alkylalcohols or polymeric alcohols include sugar alcohols such as sorbitolor polyvinyl alcohols. The at least one additive may be an alkylalcohol, an alkyl ethoxylate, or a propylene oxide derivative thereof.Exemplary alkyl alcohols, alkyl ethoxylates, or propylene oxidederivatives that can be used as at least one additive within animmersion fluid may be represented by formulas IVa through IVe. Aspecific example of a Formula IVd additive is2,4,7,9-tetramethyl-4,7-decane diol. Examples of Formula IVe additivesinclude, but are not limited to, 3,5-dimethyl-1-hexyn-3-ol and2,6-dimethyl-4-heptanol. The at least one additive may be an alkyl acidester such as an alkyl carboxylate. Exemplary alkyl carboxylates oralkyl acid esters that can be used as at least one additive within animmersion fluid may be represented by formulas Va through Vc. An exampleof a Formula Va additive includes, but is not limited to, diisopentyltartrate. The at least one additive may be an alkyl amine having one ormore amine groups including primary, secondary and tertiary amines or analkyl amine ethoxylate. Exemplary alkyl amines or alkyl amineethoxylates that can be used as at least one additive within animmersion fluid may be represented by formulas VIa through VIe. Anexample of a Formula VIa additive includes, but is not limited to,N,N′-bis(1,3-dimethylbutyl) ethylene diamine. The at least one additivemay be an alkyl polyglycoside. An exemplary alkyl polyglycoside that canbe used as at least one additive within an immersion fluid isrepresented by formula VII. The at least one additive may be a blockoligomer or a polymer of ethylene and propylene oxide. Exemplary blockoligomers or polymers of ethylene and propylene oxide that can be usedas at least one additive within an immersion fluid may be represented byformulas VIIIa through VIIIc. The at least one additive may be aglycidyl ether or a glucamine derivative with an alkyl amine, an alkyldiamine, an alkyl alcohol, or an acetylenic alcohol. Exemplary glycidylether or glucamine derivatives that can be used as at least one additivewithin an immersion fluid may be represented by formulas IXa throughIXb. An example of a Formula IXb additive includes, but is not limitedto, an adduct of diethylenetriamine and n-butyl glycidyl ether. The atleast one additive may be an urea, such as, for example, an alkyl ureaor a dialkyl urea. The at least one additive may be a fluorinated orpartially fluorinated acetylenic alcohol or diol and derivativesthereof. Exemplary fluorinated or partially fluorinated acetylenicalcohol or diol and derivatives thereof that can be used as at least oneadditive within an immersion fluid may be represented by formulas XIathrough XIe. An example of a Formula XIa additive includes, but is notlimited to, hexafluoropropanol acetylene.

The at least one additive may be a fluorosurfactant provided that thecarrier medium comprises at least 1% by weight or greater of an aqueousfluid. Exemplary fluorosurfactants include: straight, branched, orcyclic hydrofluorocarbons having 2 to 10 carbon atoms wherein there aremore fluorine atoms than hydrogen atoms;F[CF(CF₂)CF₂]_(n)—O—[CH₂CH₂O]_(m)—H; F(CF₂(CF₃)CF₂O]_(n)CFHCF₃ wherein nis a number ranging from 1 to 5; F[CF(CF₃)CF₂O]_(n)CF₂CF₃ wherein n is anumber ranging from 1 to 5; and HCF₂(OCF₂)_(n)(OCF₂CF₂)_(m)—O—CF₂Hwherein (n+m) is a number ranging from 1 to 8; a mixture of the ammoniumsalts of perfluorocarboxylic acids; fluoroaliphatic esters,[F(CF₂CF₂)₁₋₇CH₂CH₂O]_(x)P(O)(ONH₄)_(y) where x=1 or 2; y=2 or 1; andx+y=3 in various weight solution of isopropanol in water ranging from25-70%; [F(CF₂CF₂)₁₋₇CH₂CH₂O]_(x)P(O)(OH)_(y) where x=1 or 2; y=2 or 1;and x+y=3; F(CF₂CF₂)₃—8CH₂CH₂SO₃H in a 4.5% by weight solution of aceticacid in water; ammonium salt of perfluoro-octanoic acid.

In certain embodiments, the at least one additive may be a salt.Exemplary salts include: metal salts, ammonium salts, sulfonium salts,phosphonium salts, halide salts, sulfate salts, sulfide salts, sulfonatesalts, sulfite salts, phosphate salts, phosphonate salts, phosphitesalts, and derivatives thereof. Examples of metal salts include alkaliearth metal salts, such as barium chloride, calcium fluorophosphatesdehydrate, calcium fluoride (n=1.4338), magnesium chloride, andmagnesium sulfate; alkali metal salts such as lithium chloride,potassium chloride, sodium chloride (n=1.5443), sodium bisulfite, cesiumbisulfate, cesium hydrogen phosphate, cesium methane sulfonate, cesiumperchlorate, and cesium phosphate; and transition metal salts such ascadmium chloride. In certain embodiments, the salt may be a phosphoniumsalt such as, for example, tetrabutylphosphonium chloride,tetrabutylphosphonium methane sulfonate, tetrabutylphosphoniumphosphate, tetrabutylphosphonium bromide, tetraoctylphosphonium bromide,trihexyl(tetradecyl)-phosphonium hexafluorophosphate,trihexyl(tetradecyl)-phosphonium hexafluorophosphate, andtrihexyl(tetradecyl)-phosphonium bis(trifluoromethylsulfonyl)imide. Incertain embodiments, the salt may be a sulfonium salt such as, forexample, a trialkyl sulfonium salt such as trimethylsulfonium salt. Incertain embodiments, the salt may be a sulfate salt or an alkyl or alkylethoxylate derivative thereof such as, for example, dimethyl sulfate,dodecyl sulfate sodium salt, methyl (tributyl)-phosphonium methylsulfate, sodium dodecyl sulfate, sodium octyl sulfate, zinc sulfate,cadmium sulfate, cesium sulfate, and lanthanum sulfate. In certainembodiments, the salt may be a sulfonate salt such as, for example, analkyl sulfonate, an alkyl ethyoxylate sulfonate, adamantemetanesulfonate, potassium adamantane sulfonate, and sodium xylene sulfonate.In certain embodiments, the salt may be a halide salt such as, forexample, aluminum chloride, aluminum bromide, aluminum fluoride, andaluminum iodide. The at least one additive may be an ammonium salt suchas alkyl ammonium salt.

In certain embodiments, the at least one additive may be an electrolyte.In certain particular embodiments, the electrolyte may exhibit arefractive index equal to or greater than that of water and a specificabsorbance less than 1 cm⁻¹, or less than 0.5 cm⁻¹, at an operatingwavelength ranging from 140 to 365 nm. In embodiments wherein theoperating wavelength is 193 nm, the refractive index is equal to orgreater than 1.44.

In certain embodiments, the immersion fluid may contain an ionic liquid.The term “ionic liquid” as used herein describes an organic salt that isliquid at, or close to room temperature. In these embodiments, the ionicliquid may be added to the immersion fluid as an additive to, forexample, an aqueous fluid and/or a non-aqueous fluid. Examples ofsuitable ionic liquids that can be used herein include lanthanum IIItrifluoromethane sulfonate, tetramethyl ammonium hexafluorophosphonate,tetrabutylphosphonium, tris(pentafluoroethyl)trifluorophosphate,tetraethylammonium bis(malonato(2-)borate, and1-ethyl-1-methylpyrrolidinium hexafluorophosphate.

Various other components may be optionally added to the immersion fluid.These components may include, but are not limited to, stabilizers,dissolving aids, colorants, wetting agents, antifoamers, bufferingagents, and other additional surfactants. Generally, the amount of eachof these additives would be about 0.0001 to 1 percent by weight, orabout 0.0001 to 0.1 percent by weight, based upon the total weight ofthe immersion fluid. In embodiments where one or more additionalsurfactants are added to the immersion fluid, the surfactant may be anyof the surfactants disclosed herein or provided in the referenceMcCutcheon's Emulsifiers and Detergents.

In embodiments where the immersion fluid contains at least one additive,the immersion fluid may be prepared by mixing the at least one additivewith at least one carrier medium which can be an aqueous and/ornon-aqueous fluid and any additional components. In certain embodiments,one or more aqueous fluids such as ultra pure or HPLC water is combinedwith from about 1 ppm to the maximum solubility limit, or from about 1ppm to about 50% by weight or from about 10 ppm to about 10,000 ppm, ofat least one additive to provide the immersion fluid. In an alternativeembodiment, from about 1 ppm to the maximum solubility limit, or fromabout 1 ppm to about 50% by weight, or from about 10 ppm to about 10,000ppm, of at least one additive is combined with one or more aqueousfluids until a homogeneous mixture is formed and is then combined withone or more non-aqueous fluids to provide the immersion fluid. In astill further embodiment, one or more non-aqueous fluids such as thefluids disclosed herein are combined with from about 1 ppm to themaximum solubility limit of at least one additive to provide theimmersion fluid. In the foregoing embodiments, the combining may be doneat a temperature range of from about 20 to 60° C. or from about 40 to60° C. to affect dissolution of the ingredients contained therein andprovide a homogeneous mixture. The resulting immersion fluid mayoptionally be filtered to remove any undissolved particles that couldpotentially harm the substrate.

In alternative embodiments, the immersion fluid may comprise the carriermedium, i.e., at least one aqueous fluid, at least one non-aqueousfluid, and mixtures thereof. In embodiments wherein the immersion fluidis a mixture of carrier media, the combining may be done at atemperature range of about 20 to 60° C. or from 40 to 60° C. to providea homogeneous mixture.

The immersion fluid is preferably used to treat at least a portion ofthe surface of a substrate that is coated with a photoresist or resistcoating. Suitable substrates include, but are not limited to, materialssuch as gallium arsenide (“GaAs”), silicon, tantalum, copper, ceramics,aluminum/copper alloys, polyimides, and compositions containing siliconsuch as crystalline silicon, polysilicon, amorphous silicon, epitaxialsilicon, silicon dioxide (“SiO₂”), silicon nitride, doped silicondioxide, and the like. Further exemplary substrates include silicon,aluminum, or polymeric resins. In certain embodiments, the immersionfluid contacts at least a portion of a substrate coated with aphotoresist, or a resist-coated substrate and is substantiallynon-reactive to the resist coating. Exemplary resist coatings include,but are not limited to, novolac resin, polyvinyl phenol copolymer, orcopolymers of p-hydroxystyrene and t-butyl acrylate.

The immersion fluid is applied to at least a portion of a substratehaving a photoresist coating applied thereto. The photoresist-coatedsubstrate is then exposed to radiation through an optical device toprovide a pattern that is imposed upon the photoresist coating. Examplesof radiation sources that may be used include ultraviolet (uv) light,electron beam, x-ray, laser, lamp, or ion beams. In certain embodiments,the radiation source emits light at wavelengths at an operatingwavelength ranging from 140 nm to 365 nm such as 193 nm and 157 nm. Insome embodiments, a pre-bake or soft-bake step may be conducted prior tothe exposure step. This pre-bake or soft bake step may be conducted, forexample, at a temperature ranging from 90° C. to 150° C. for a time orfrom 30 to 120 seconds on a hot plate.

Depending upon whether the photoresist coating is positive or negative,the radiation either increases or decreased its solubility in asubsequently applied alkaline developer solution such as a processsolution containing tetramethylammonium hydroxide (TMAH), potassiumhydroxide, sodium hydroxide, or other base. Further examples ofdeveloper solutions include those provided in U.S. Pat. Nos. 6,455,234;6,268,115; 6,238,849; 6,127,101; and 6,120,978. In a positivephotoresist coating, the areas masked from radiation remain afterdevelopment while the exposed areas are dissolved away. In a negativephotoresist coating, the opposite occurs. The immersion fluid of thepresent invention may be suitable to treat substrates having eitherpositive or negative photoresist coatings. The patterned photoresistimage may be developed by a variety of different means, including by notlimited to quiescence, immersion, spray, or puddle development. Afterthe patterned photoresist image is developed, the substrate is baked toharden the polymer contained within the photoresist. The bake step maybe conducted, for example, at a temperature ranging from 70° C. to 150°C. for a time duration of from 30 to 120 seconds.

A typical immersion lithography process uses an apparatus that has aservo motor driven wafer stage that supports and positions aresist-coated substrate or wafer underneath an optic device such as alens. The optic device may also be a prism, a mirror or combinationsthereof. The immersion fluid is dispensed onto at least a portion ofresist-coated substrate through one or more nozzles to form a puddle. Aradiation source that emits light at the operating wavelength thenpasses through lens and the puddle of immersion fluid prior to exposureto at least a portion of the resist-coated substrate.

The immersion fluid is preferably applied to the photoresist-coatedsubstrate as a prepared solution. In alternative embodiments, however,the immersion fluid can be prepared within the application stream justprior to or during contact with the substrate surface. For example, acertain quantity of one or more additives can be injected into acontinuous stream of aqueous fluid and/or non-aqueous fluid medium orimmersion fluid that optionally includes additives thereby forming theimmersion fluid. In some embodiments of the present invention, a portionof the at least one additive may be added to the substrate afterapplication of the immersion fluid. In still other embodiments of thepresent invention, the at least one additive can be also deposited uponor comprise the material of a high surface area device such as acartridge or filter (which may or may not include other components). Astream of aqueous fluid and/or non-aqueous fluid then passes through thecartridge or filter thereby forming the immersion fluid. In stillanother embodiment of the present invention, the immersion fluid isprepared during the contacting step. In this connection, at least oneadditive is introduced via a dropper or other means to the surface ofthe substrate. Aqueous fluid and/or non-aqueous fluid medium is thenintroduced to the surface of the substrate and mixes with the at leastone additive on the surface of the substrate thereby forming theimmersion fluid.

In an alternative embodiment of the invention, a concentratedcomposition comprising at least one additive is provided that may bediluted in an aqueous fluid and/or non-aqueous fluid medium to providethe immersion fluid. A concentrated composition of the invention, or“concentrate” allows one to dilute the concentrate to the desiredstrength and pH. A concentrate also permits longer shelf life and easiershipping and storage of the product.

A variety of means can be employed in contacting the immersion fluidwith the substrate surface. The actual conditions of the contacting step(i.e., temperature, time, and the like) may vary over wide ranges andare generally dependent on a variety of factors such as, but not limitedto, the nature and amount of residue on the surface of the substrate andthe hydrophobicity or hydrophilicity of the substrate surface, etc. Thecontact step can be conducted in either a dynamic method such as, forexample, a streamline process for applying the immersion fluid over thesurface of the substrate or in a static method such as, for example, apuddle application. The immersion fluid may also be sprayed onto thesurface of the substrate in a dynamic method such as in a continuousprocess or sprayed onto the surface and allowed to remain there in astatic method. The duration of the contacting step, or time of contactof the immersion fluid to the substrate surface, can vary from afraction of a second to hundreds of seconds. Preferably, the durationcan range from 1 to 200 seconds, or from 1 to 150 seconds, or from 1 to40 seconds. The temperature range for the contacting step can vary from10 to 100° C, or from 10 to 40° C.

EXAMPLES Example 1 Dynamic Surface Tension

The dynamic surface tension (DST) data was collected via the maximumbubble pressure method described in Langmuir 1986, 2, pp. 428-432. Thedata was collected at bubble rates that range from 0.1 bubbles/second(b/s) to 20 b/s using the Kruss BP2 bubble pressure tensiometermanufactured by Kruss, Inc. of Charlotte, N.C.

The dynamic surface tension data provides information about theperformance of the at least one additive at conditions fromnear-equilibrium (0.1 b/s) to relatively high surface creation rates (20b/s). High bubble rates may correspond to a dynamic liquid injectionprocess in an immersion lithography process. It is desirable that thedynamic surface tension by reduced below that of ultrapure water at highbubble rates (i.e., 70-72 dyne/cm at 20 b/s) to provide, inter alia,better wetting of the photoresist-coated substrate. Table I provides theDST of immersion fluids containing varying concentrations of the alkyldiol additive 2,4,7,9-tetramethyl-4,7-decane diol added to a 100 mLquantity of the aqueous fluid ultra pure water. The alkyl diol additiveis added to the ultra pure water at ambient temperature while stirringto provide a homogeneous solution. The immersion fluids exhibiteddynamic surface tensions at high bubble rates below that of water or 72dyne/cm. This indicates that the immersion fluid of the presentinvention may be effective at reducing the surface tension of water in adynamic process. TABLE I Dynamic Surface Tension DST DST DST DST DSTAdditives (dyne/cm) (dyne/cm) (dyne/cm) (dyne/cm) (dyne/cm) Conc. 0.1b/s 1 b/s 6 b/s 15 b/s 20 b/s 0.01 wt % 48.7 54.0 61.9 67.8 69.0 0.03 wt% 41.8 43.7 47.5 53.6 56.5 0.05 wt % 38.5 39.6 41.8 45.6 47.6

Example 2 Wetting Property

The wetting properties of immersion fluids containing an alkyl dioladditive, 2,4,7,9-tetramethyl-4,7-decane diol, and ultra pure water as acomparison, was measured on the G10/DSA10 Kruss drop shape analyzerprovided by Kruss USA of Charlotte, N.C. using the Sessile drop method.In this method, the wetting properties of a localized region on thesurface of a photoresist-coated substrate are estimated by measuring thecontact angle between the baseline of a droplet of aqueous developersolution and the tangent at the droplet base. A high-speed cameracaptured the spreading of the droplet at a speed of 2 frames per secondfor 2 minutes and the contact angle was measured. The photoresist is atypical acrylate type 193 nm resist.

In general, lower contact angles indicate better wetting properties onresist surface. As Table II illustrates, the addition of additiveimproved the wetting on the resist surface. TABLE II Comparison ofContact Angles of UPW vs. Immersion Fluid Contact Contact ContactContact Angle Angle Angle Angle Fluid (0 sec) (5 sec) (10 sec) (30 sec)Ultra pure 62.9 62.9 62.5 61.6 water 0.02 wt % 54.1 53.5 52.8 51.8additive

Example 2a Through 2e and Comparative Example (HPLC water)

A quantity of 0.01% by weight or 100 ppm of the following additives:hydrophobically modified acetylenic diol or oxirane [(2-EthylHexyl)Oxy]Methyl]-, Rx prod w/polyethylene glycol ether with2,4,7,9-tetramethyl-5-decyne-4,7-diol (2:1);2,4,7,9-tetramethyl-4,7-decane diol; ethoxylated2,4,7,9-tetramethyl-4,7-decane diol; polysiloxane-polyester copolymer orTEGOWE™ manufactured by Goldschmidt Chemical of McDonald, Pa.; and anethoxylated nonionic fluorosurfactant or ZONYL™ FSO with the formula:F(CF₂CF₂)1-7CH₂CH₂O(CH₂CH₂O)yH where y=0 to ca. 15 manufactured byDupont of Wilmington, Del. were each combined with 100 mL of the aqueousfluid HPLC water manufactured by Aldrich Chemical to provide immersionfluids 2 a through 2 e, respectively. The additives were added to theaqueous fluid, HPLC water, at ambient temperature while stirring toprovide a homogeneous mixture. Dynamic contact angle measurements, orthe contact angle measurement over a period of time, measured onunexposed 193 nm photoresist-coated substrates for each of the immersionfluids 2 a through 2 e and HPLC water as a comparative were obtained inaccordance with the method disclosed in Example 2. The results of thedynamic contact angle measurements are provided in FIG. 1.

Example 3

The absorbance of immersion fluids was measured with a UV spectrometer.The wavelength was scanned from 210 nm to 185 nm. As shown in FIG. 2, at193 nm wavelength, the addition of 0.02wt % of the additive2,4,7,9-tetramethyl-4,7-decane diol only increased the absorbanceslightly. The additive is enough to lower the contact angle on resist by15% while only adding 0.03-0.05 cm⁻¹ to the absorbance. This absorbanceis low enough to allow 1 mm working distance between optics and resistsurface which maintaining the total transmission >95%. The improvedwetting may lead to more uniform image formation across the wafer andenhance the image resolution.

Example 4

A quartz crystal microbalance (QCM) was used to study changes in filmthickness of unexposed 193 nm photoresist solutions. A CH Instrumentsmodel CHI 405 was used as a driver and high-resolution frequencycounter. The instrument was fitted with a flow cell. The quartz crystalswere made by International Crystal Manufacturing. The electrode wasgold, 1000 Å thick and 0.201″ in diameter. The crystal resonancefrequency was 7.995 MHz +/−10 Hz. The quartz crystals were spin-coatedwith a photoresist solution. The spin recipe was 1200 revolutions perminute (RPM) for 30 seconds and 3000 RPM for 10 seconds. The post applybake (PAB) was 4 min at 125° C. The crystals were then exposed to UVlight for the desired time. Each crystal was then mounted on a sensorprobe and placed in the liquid flow cell. The instrument was controlledby a Dell PC using CHI software program. Frequency data was collectedevery 0.01 second. The flow of immersion fluid containing 0.01 weightpercent of at least one additive was started 15 seconds after dataacquisition started, to ensure that there were no glitches in the dataacquisition process. The residence time through the flow cell wasapproximately 2 seconds. The experiment was stopped after 2 minutes.FIG. 3 provides a comparison of the change in film thickness in nm forimmersion fluids containing 0.01% by weight or 100 ppm of the additivesdimethyl-4-heptanol, hydrophobically modified acetylenic diol, andethoxylated nonionic fluorosurfactant in 100 ml of ultrapure water andultrapure water as a comparative.

Example 5

Various immersion fluids containing 0.01% by weight of at least oneadditive in 200 ml of the aqueous fluid ultrapure water were prepared atambient temperature by mixing to form a homogeneous solution. Eachimmersion fluid was tested for foam dissipation using the Ross-Milesfoam height test or ASTM D1173-53. The results of this test for eachimmersion fluid is provided in Table III. TABLE III Time to 0 DynamicInitial Foam foam Foam Additive Height (cm) (seconds) Height (1)2,4,7,9-tetramethyl-decane-4,7-diol 0 0 0 2-Hydroxy-succinic aciddibutyl 1.5 0 0 ester Ethoxylated 2,4,7,9-tetramethyl- 1.3 30 05-decyn-4,7-diol Hydrophobically modified 1.7 >300 1.0 acetylenic diolPolysiloxane-polyester copolymer 0.4 3 0(1) Remaining foam after 1 minute measured in cm.

Example 6a though 6j

Various immersion fluids were prepared at ambient temperature by mixingto form a homogeneous solution. The identity of the carrier medium thatcomprises the immersion fluid, and the additive within the immersionfluid if present, are provided in Table IV. The optical properties,i.e., the absorption, absolute refractive index, and the change inrefractive index with temperature (dn/dT), of the exemplary immersionfluids and a comparative example HPLC water were measured and theresults are provided in Table IV. FIG. 4 compares the absoluterefractive index of various immersion fluids disclosed herein measuresat a wavelength of 193 nm. The absorption, or A/I, was measured using adouble beam UV-Visible Light, Lamda 900 Spectrometer manufactured byPerkin-Elmer at a wavelength of 193 nm. The absolute refractive indexwas measured using an experimental unit referred to VUV Hilger-ChanceRefractometer/Goniometer at a wavelength of 193 nm and temperature of21.5° C. The change in refractive index with temperature (dn/dT) wasmeasured by placing the fluid samples in a V-Groove fused silica cellinto a goniometer, which is temperature-controlled and sealed from theatmosphere under stringent temperature control (±0.01° C. The goniometerobtained measurements of absolute refractive index with absorptionpath-lengths ≧500 μm at a wavelength of 193 nm or 157 nm.

The results in Table IV illustrate that the immersion fluids describedherein can provide a higher refractive index and a dn/dT of zerorelative to that of Comp. Ex. or water. In certain instances, immersionfluids having a relatively higher refractive index may enable NumericalApertures (NA>1) needed for sub-45 nm nodes. Use of these fluids mayalso greater depth of focus to be achieved and may bridge the gapbetween water-based 193 nm Immersion and Extreme-UV lithography.

Dynamic contact angle measurements, or the contact angle measurementover a period of time, measured on unexposed 193 nm photoresist-coatedsubstrates for immersion fluids 6b, 6g, 6j, 6k, and 6k and HPLC water asa comparative were obtained in accordance with the method disclosed inExample 2. The results of the dynamic contact angle measurements areprovided in FIG. 5. TABLE IV Absorption Carrier (cm−1) @ n @ 193 nmExample Additive Medium 193 nm (21.5° C.) dn/dT (° C.) Comp. Ex. — Water(HPLC) 0.0400 1.4366 −1.00E−04 Ex. 6a Zinc Sulfate (50%) Water (HPLC)3.3050 1.4884 −1.60E−04 (50%) Ex. 6b Cesium methane Water (HPLC) 1.93901.5154 — sulfonate (70%) (30%) Ex. 6c Trimethylsulfonium Water (HPLC)2.6230 1.4885 — methyl sulfate (60%) (40%) Ex. 6d — 1,3-Butanediol5.4860 1.4656 −1.60E−04 Ex. 6e Polyvinyl alcohol Water (HPLC) 5.39701.4556   7.90E−05 (10%) (90%) Ex. 6f — Glycerol >6 1.6159 −2.88E−04 Ex.6g — Dodecane 1.1440 1.5573 — Ex. 6h — Bicyclohexyl >6 1.6438 −7.30E−04Ex. 6i — Cyclohexane 1.5230 1.5655 — Ex. 6j — Methane 0.9400 1.5010−2.50E−04 sulfonic acid (50%)/Water (HPLC) (50%) Ex. 6k — Decalin >61.5606 — Ex. 6l — Glycerol >6 1.5727 — (50%)/Water (HPLC) (50%)

1. An immersion fluid having a transmission of 50% or greater at anoperating wavelength ranging from 140 nm to 248 nm comprising: at leastone carrier medium selected from the group consisting of bicyclohexyl,glycerol, and cis-2-methylcyclohexanol; and about 1 ppm to a maximumsolubility limit of at least one additive selected from an alkylalcohol; an alkyl ethoxylate, an alkyl propoxylate and derivativethereof; an alkyl acid ester; an alkyl amine comprising an amine group;an alkyl amine ethoxylate; an acetylenic alcohol, an acetylenic diol andethylene oxide/propylene oxide derivatives thereof; an alkylpolyglycoside; a block oligomer; a polymer of ethylene and propyleneoxide; a glycidyl ether; a glucamine derivative of a glycidyl ether; aurea; a siloxane-containing compound; a fluorinated or partiallyfluorinated acetylenic alcohol, and diols and derivatives thereof.
 2. Amethod of forming a pattern on a substrate coated with a layer ofphotoresist, the method comprising the steps of: introducing a fluidbetween the layer of photoresist on the substrate and a lens having anoperating wavelength ranging from 140 nm to 365 nm, wherein the fluidcomprises: at least one carrier medium selected from the groupconsisting of an aqueous fluid, a non-aqueous fluid, and mixturesthereof wherein the at least one carrier medium has a refractive indexgreater than or equal to water at the operating wavelength; and about 1ppm to a maximum solubility limit of at least one additive selected froman alkyl alcohol; an alkyl ethoxylate, an alkyl propoxylate, andderivative thereofs; an alkyl acid ester; an alkyl amine comprising anamine group; an alkyl amine ethoxylate; an acetylenic alcohol, anacetylenic diol, and ethylene oxide/propylene oxide derivatives thereof;an alkyl polyglycoside; a block oligomer; a polymer of ethylene andpropylene oxide; a glycidyl ether; a glucamine derivative of a glycidylether; an urea; a siloxane-containing compound; a fluorinated orpartially fluorinated acetylenic alcohol, diol and derivatives thereof;a fluorosurfactant; an ionic liquid; a salt; and an electrolyte,provided that if the at least one additive is a fluorosurfactant thenthe immersion fluid comprises about 1% by weight or greater of anaqueous fluid; and exposing the layer of the photoresist on thesubstrate through the fluid to form a pattern upon the photoresist. 3.The method of claim 2 wherein the at least one carrier medium is anaqueous fluid.
 4. The method of claim 3 wherein the at least oneadditive is selected from the group consisting of an alkyl alcohol, anionic liquid, a salt, an electrolyte, and mixtures thereof.
 5. Themethod of claim 2 wherein the at least one carrier medium is anon-aqueous fluid.
 6. The method of claim 5 wherein the non-aqueousfluid is at least one selected from the group consisting of:bicyclohexyl, glycerol, and cis-2-methylcyclohexanol.
 7. The method ofclaim 6 wherein the non-aqueous fluid is bicyclohexyl.
 8. The method ofclaim 2 wherein the at least one carrier medium is a mixture of anaqueous and a non-aqueous fluid and wherein the non-aqueous fluid iswater miscible.
 9. The method of claim 8 wherein the non-aqueous fluidis at least one selected from the group consisting of: methanol,ethanol, isopropyl alcohol, glycerol, ethylene glycol and derivativesthereof, polyethylene glycol and derivatives thereof, andtetrahydrofuran.
 10. A method of forming a pattern on a substrate coatedwith a layer of photoresist, the method comprising the steps of:introducing a fluid between the layer of photoresist on the substrateand a lens having an operating wavelength ranging from 140 nm to 365 nm,wherein the fluid comprises: at least one carrier medium selected fromthe group consisting of: an aqueous fluid, a non-aqueous fluid, andmixtures thereof, wherein the at least one carrier medium has arefractive index greater than or equal to water at the operatingwavelength; and about 10 ppm to a maximum solubility limit of at leastone additive selected from an alkyl alcohol or a polymeric alcoholhaving one or more hydroxyl groups; and exposing the layer of thephotoresist on the substrate through the fluid to form a pattern uponthe photoresist.
 11. The method of claim 10 wherein the at least onecarrier medium is a mixture of an aqueous and a non-aqueous fluid andwherein the non-aqueous fluid is water miscible.
 12. The method of claim11 wherein the non-aqueous fluid is at least one selected from the groupconsisting of: methanol, ethanol, isopropyl alcohol, glycerol, ethyleneglycol and derivatives thereof, polyethylene glycol and derivativesthereof, and tetrahydrofuran.
 13. The method of claim 10 wherein the atleast one carrier medium is a non-aqueous fluid.
 14. The method of claim13 wherein the non-aqueous fluid is at least one selected from the groupconsisting of: bicyclohexyl, glycerol, and cis-2-methylcyclohexanol. 15.The method of claim 14 wherein the non-aqueous fluid is bicyclohexyl.16. The method of claim 13 wherein the non-aqueous fluid is ahydrocarbon.